The present invention relates to communication between a peripheral device and a host device via multiple bus interfaces, and particularly, to a wireless webcam which can be powered through a USB bus.
The use of numerous peripheral devices has become pervasive. Each host (e.g., a user's personal computer) often has several peripheral devices connected to it, such as keyboards, mice, trackballs, webcams, other digital cameras, joysticks, gamepads, personal digital assistants (PDAs), portable media players, and so on. Each of these peripheral devices often have several data interfaces for communicating with the host, such as a parallel port, a USB port, a wireless transceiver, etc.
The USB standard allows peripheral devices to both have data communication and receive power over the same cable. This has spawned many types of devices. For example, devices that provide data by other means, such as wireless, might connect to a USB port simply to receive power. A docketing station and special power port may provide that only the power connectors are used. Wireless USB devices can transmit to a dongle receiver plugged into a USB port on a computer. Other devices may provide both wireless and wired connections, with the user being able to select which one is more appropriate at any given time.
While any of such multiple data interfaces can be used to connect the device to the host, it is not conventionally possible to change the interface used to carry the data stream between the peripheral and the host without needing to interrupt the data stream in some way and therefore disrupt the user experience. For example, the user may be required to exit or close the application using the device and to re-enter or re-start the application using the new interface. Even where the user is not required to exit and re-enter the application, methods of automatically switching the data stream between data interfaces may cause unnecessary opportunities for disruption of the user experience.
In one exemplary scenario where the user is involved in a video instant messaging (VIM) conversation using a wireless webcam and an instant messaging application, the battery of the wireless webcam may be running low and the user may be required to dock the wireless webcam in a docking station to provide continued operating power to the webcam. The docking station may be configured to communicate with the user's PC (i.e., the host device) via a USB interface. Generally, when a USB enabled peripheral device is connected to a plug-and-play USB bus of the host device, the host device detects the peripheral device and automatically begins the process of communicating with the peripheral device via the connected pins to initiate the data stream between the two devices.
Accordingly, there is a need for a system and method for managing the data stream so as to limit unnecessary transfers between data interfaces and attendant disruptions.